The present invention relates to a fuel control system for an engine having an electronic fuel injection system, and more particularly to a control system for performing dashpot operation at release of an accelerator pedal of a motor vehicle during the driving of the vehicle.
In a conventional engine having an idle speed control valve in a bypass around a throttle valve, a dashpot control system is provided for delaying closing the idle speed control valve when the accelerator pedal is released to turn on an idle switch, so as to prevent engine speed from suddenly reducing. At the same time, fuel injectors are closed by a signal of the idle switch to cut off the fuel supply, for improving fuel consumption. Japanese Patent Applications Laid-Open Nos. 56-20735 and 58-25544 disclose such a fuel cut off system.
However, when the fuel is cut off, the power of the engine is greatly reduced. As a result, the operation by the dashpot control system is not effected, and hence large deceleration shock arises at the release of the accelerator pedal.